Proximity sensors of various types are used in a variety of applications in which the distance to an object and, in some circumstances, the closing velocity of that object are to be determined. This data is often provided to a processing system for analysis. Typically, this analysis determines whether one or both of the distance and velocity exceed a predetermined safety threshold and whether an alarm is to be set or other action taken. Proximity sensors are used, for example, in a variety of applications that can include burglar alarms, obstacle detection, and automobiles. Proximity sensors in automobiles are used to determine the relative position and closing velocity of other automobiles or objects in the vicinity of the automobile. These sensors must be physically small, light weight, highly reliable, and low cost. The requirements of the systems that utilize these sensors are often quite stringent both in terms of performance and in the physical and economic factors as well. The more complex the sensor, the larger the parts count, and concomitantly, the higher the cost, the higher the mass, the larger the physical volume of the sensor and the lower the reliability of the sensor.
Therefore, it would be desirable to provide a sensor that utilizes fewer components to reduce the cost, size, and weight of the sensor and provide the necessary functionality and reliability.